[lit] Test /dev/null support on Windows.

[zturner]

This might be a dumb question, but in Windows you can use NUL instead of /dev/null. Instead of all this hackery around temp files, why don't we just replace /dev/null with NUL?

[rnk]

In D44771#1045875, @zturner wrote:

This might be a dumb question, but in Windows you can use NUL instead of /dev/null. Instead of all this hackery around temp files, why don't we just replace /dev/null with NUL?

We should do that, but I consider it future work. It will require more testing. I have a feeling if you just say open("NUL", mode) you will create a file called "NUL" in the cwd. It's not something you can feed to generic filesystem APIs.

utils/lit/tests/unit/TestRunner.py

105

This should match the 4 space indent.

[amccarth]

In D44771#1046003, @rnk wrote:

I have a feeling if you just say open("NUL", mode) you will create a file called "NUL" in the cwd. It's not something you can feed to generic filesystem APIs.

No, it won't create a file named NUL. The special file names are handled at a relatively low level in the Windows stack (below _open). You would have to use a namespace escape like \\?\ to avoid having Windows treat your special file name as a regular name. The special names are: CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9.

[mtrofin]

Spaces (2->4)

[rnk]

I ran the tests, and the unit tests don't pass because the /dev/null replacement happens much later during test execution, not command parsing. Unit testing the text executor would require much more faking/mocking than is really worth it. I would be comfortable making this change include a revert of rL328157. That will exercise the new replacement enough.

[mtrofin]

Revert "[llvm-profdata] Use "-o /dev/null" in invalid-profdata.test"

[mtrofin]

• [lit] windows dev null shshell test

[rnk]

Looks good after reverting the unit test that didn't work.

utils/lit/tests/Inputs/shtest-shell/dev-null.txt

1 ↗

(On Diff #139728)

New test looks good, thanks!

utils/lit/tests/unit/TestRunner.py

108

This test still fails because the parser doesn't do the replacement. You need to revert changes to this file and probably testrunner-custom-parsers/test.txt before committing or tests will fail on Windows.

[mtrofin]

Revert old test changes.

test/tools/llvm-profdata/invalid-profdata.test

 RUN: echo "# NumValueSites:"                             >> %t.input
 RUN: echo "2"                                            >> %t.input
 RUN: echo "2"                                            >> %t.input
 RUN: echo "f1:10"                                        >> %t.input
 RUN: echo "f2:0"                                         >> %t.input
 RUN: echo "1"                                            >> %t.input
 RUN: echo ":10"                                          >> %t.input
 
-RUN: not llvm-profdata merge %t.input -text -o /dev/null 2>&1  | FileCheck %s --check-prefix=BROKEN
+RUN: not llvm-profdata merge %t.input -text -output=/dev/null 2>&1  | FileCheck %s --check-prefix=BROKEN
 BROKEN: Malformed instrumentation profile data
 
 RUN: echo ":ir"                     > %t.input
 RUN: echo "_ZN6Thread5StartEv"      >> %t.input
 RUN: echo "# Func Hash:"            >> %t.input
 RUN: echo "288793635542036872"      >> %t.input
 RUN: echo "# Num Counters:"         >> %t.input
 RUN: echo "3"                       >> %t.input

utils/lit/lit/TestRunner.py

 
 kIsWindows = platform.system() == 'Windows'
 
 # Don't use close_fds on Windows.
 kUseCloseFDs = not kIsWindows
 
 # Use temporary files to replace /dev/null on Windows.
 kAvoidDevNull = kIsWindows
+kDevNull = "/dev/null"
 
 class ShellEnvironment(object):
 
     """Mutable shell environment containing things like CWD and env vars.
 
     Environment variables are not implemented, but cwd tracking is.
     """
 
for (index, r) in enumerate(redirects):
             continue
 
         redir_filename = None
         name = expand_glob(filename, cmd_shenv.cwd)
         if len(name) != 1:
            raise InternalShellError(cmd, "Unsupported: glob in "
                                     "redirect expanded to multiple files")
         name = name[0]
-        if kAvoidDevNull and name == '/dev/null':
+        if kAvoidDevNull and name == kDevNull:
             fd = tempfile.TemporaryFile(mode=mode)
         elif kIsWindows and name == '/dev/tty':
             # Simulate /dev/tty on Windows.
             # "CON" is a special filename for the console.
             fd = open("CON", mode)
         else:
             # Make sure relative paths are relative to the cwd.
             redir_filename = os.path.join(cmd_shenv.cwd, name)
for i,j in enumerate(cmd.commands):
         if not executable:
             executable = lit.util.which(args[0], cmd_shenv.env['PATH'])
         if not executable:
             raise InternalShellError(j, '%r: command not found' % j.args[0])
 
         # Replace uses of /dev/null with temporary files.
         if kAvoidDevNull:
             for i,arg in enumerate(args):
-                if arg == "/dev/null":
+                if kDevNull in arg:
                     f = tempfile.NamedTemporaryFile(delete=False)
                     f.close()
                     named_temp_files.append(f.name)
-                    args[i] = f.name
+                    args[i] = arg.replace(kDevNull, f.name)
 
         # Expand all glob expressions
         args = expand_glob_expressions(args, cmd_shenv.cwd)
 
         # On Windows, do our own command line quoting for better compatibility
         # with some core utility distributions.
         if kIsWindows:
             args = quote_windows_command(args)

utils/lit/tests/Inputs/testrunner-custom-parsers/test.txt

 
 // MY_TAG.
 // foo bar baz
 // MY_RUN: baz
 // MY_LIST: one, two
 // MY_LIST: three, four
 // MY_RUN: foo \
 // MY_RUN: bar
+// MY_RUN: command -o /dev/null
+// MY_RUN: command -output=/dev/null
 //
 // MY_CUSTOM: a b c
 //
 // END.
 // MY_LIST: five

utils/lit/tests/unit/TestRunner.py

def test_lists(self):
         self.assertEqual(list_parser.getValue(),
                               ['one', 'two', 'three', 'four'])
 
     def test_commands(self):
         parsers = self.make_parsers()
         self.parse_test(parsers)
         cmd_parser = self.get_parser(parsers, 'MY_RUN:')
         value = cmd_parser.getValue()
-        self.assertEqual(len(value), 2)  # there are only two run lines
+        self.assertEqual(len(value), 4)  # there are four run lines
         self.assertEqual(value[0].strip(), 'baz')
         self.assertEqual(value[1].strip(), 'foo  bar')
+        if platform.system() != 'Windows':
+            self.assertEqual(value[2].strip(), 'command -o /dev/null')
+            self.assertEqual(value[3].strip(), 'command -output=/dev/null')
+        else:
+            self.assertFalse('/dev/null' in value[2].strip())
+            self.assertFalse('/dev/null' in value[3].strip())
 
     def test_custom(self):
         parsers = self.make_parsers()
         self.parse_test(parsers)
         custom_parser = self.get_parser(parsers, 'MY_CUSTOM:')
         value = custom_parser.getValue()
         self.assertEqual(value, ['a', 'b', 'c'])
 
     def test_bad_keywords(self):
         def custom_parse(line_number, line, output):
             return output
-        
         try:
             IntegratedTestKeywordParser("TAG_NO_SUFFIX", ParserKind.TAG),
             self.fail("TAG_NO_SUFFIX failed to raise an exception")
         except ValueError as e:
             pass
         except BaseException as e:
             self.fail("TAG_NO_SUFFIX raised the wrong exception: %r" % e)